Metrological traceability of dimensional and electrical measurements of multi-line precision 1.85 mm air lines via comparison between NMIJ and Anritsu

Coaxial air lines are air-dielectric transmission lines with highly accurate dimensions and are used as reference impedance standards in measurement and by the calibration laboratories. An LRL calibration kit (Anritsu 3657-1) is composed of five air lines to allow calibrations from a few hundred MHz to 70 GHz. The conventional traceability for the impedance is via the dimensional measurements of the air lines. The traceable standards are gages calibrated by the NIST. There is no standard method for establishing metrological traceability of electrical line impedance measurements. Horibe and Ridler provide a good basis for comparing the dimensional and scattering parameter measurements of the coaxial air lines. This paper reports the results of the bilateral comparison on the 3657-1 kit between the NMIJ (National Metrology Institute of Japan) and Anritsu. The dimensional difference between the two laboratories was compared using normalized error. The results of the electrical measurements of 1.85 mm coaxial air lines were also used for demonstration of metrological traceability.